sirolimus

noun
si·​ro·​li·​mus | \ si-ˈrō-li-məs How to pronounce sirolimus (audio) \

Medical Definition of sirolimus

: an immunosuppressive drug C51H79NO13 that is a macrocyclic lactone obtained from a soil bacterium of the genus Streptomyces (S. hygroscopicus) and is taken orally especially to prevent rejection of transplanted organs Sirolimus (also called rapamycin) is a macrolide antibiotic that blocks proliferative responses of lymphocytes to interleukin-2 by inhibiting interleukin-2-mediated signal-transduction events.— Manuel Pascual et al., The New England Journal of Medicine, 21 Feb. 2002

called also rapamycin

Note: Sirolimus is often taken in combination with other immunosuppressive drugs (such as cyclosporine) and is marketed under the trademark Rapamune.